Modern laboratory procedures benefit greatly from automated and/or robotic handling of materials such as samples and reagents. Although specialized multi-compartment containers, such as well plates of various kinds, are of great utility for automating process for which they are suited, often there is a need to handle materials that are stored in individual containers such as vials or tubes. These are manufactured in a variety of geometries and sizes, and typically provided with caps that must be removed for access to the contents and replaced thereafter. Effective automation of the handling, de-capping, and re-capping of containers of this kind has heretofore proved an elusive goal.
Existing systems for capping and de-capping containers having caps that are removed or applied by rotation, such as screw caps, depend upon the use of specially designed caps having features such as slots, sockets, or lugs that can be engaged by a key such as a blade, driver, or wrench of complementary shape. Existing systems also require specially engineered tubes or vials, designed to be disposed in specially engineered racks provided with a locking mechanism to prevent the tubes from spinning in place while the caps are rotated, resulting in increased expense, inviting mechanical failure. The performance of these existing systems is not optimal, due in part to wear and tear on fragile plastic caps from the use of blade-like drivers to physically bind the inside of the caps and apply the force necessary to spin the cap on and off the physically restrained tube or vial. This binding eventually wears out the caps and leads to capping and de-capping failures. Other disadvantages include the added expense of otherwise unnecessary special tubes, caps, and racks, and the additional processing steps, and attendant risk of error, required to transfer substances from their original containers into the specialized tubes and caps. Finally, forcibly spinning multiple caps simultaneously without over-tightening presents a very complex mechanical challenge. A patented clutch mechanism has attempted to address this over-tightening problem, but has proven to be unreliable for automated operations.
A need exists for apparatus and methods that can reliably perform automated capping and de-capping on generic tubes and vials using generic, keyless caps, which may be disposed in a simple, inexpensive rack suitable for storage and automated handling.